Improvement in machines for cutting screws



rTED STATES PATENT OEEIGE.

JAMES S. ATKINSON, OF ORMSBY BOROUGH, PENNSYLVANIA.

IMPROVEMENT IN MACHINES FOR CUTTING SCREWS.

Specification forming part of Letters Patent No. 111,899, dated February21, 1871.

To M /whom 'it may concern Be 1t known that I, JAMES S. ATKINSON, otOrmsby Borough, in the county of Allegheny and State of Pennsylvania,have invented a new and useful Improvement in Screw-Cutting Machine 5and I do hereby declare the following to be a full, clear, and cX- actdescription thereof, reference being had by letters and liguresindicating like parts to the accompanying drawing, in which- Figure l isa side elevation of my improved screw-cutting machine. Fig. 2 is a planview thereof. Fig. 3 is a longitudinal section through the dies,die-holders, and chuck. Fig. 4L is an enlarged view, in perspective, ofthe abutment-piece; and Fig. 5 is a like view of one of the catches thatplay against it.

My invention consists in an improved construction of machine for cuttingthe threads of screw-bolts, whereby, among other advantages, a quick,instantaneous motion is given to the threading-dies in opening andclosing.

To enable others skilled in the art to make and use my improvement, Iwill describe its construction and operation.

The frame-work A is ot' any form or construction suitable for supportingthe operative devices. The hollow spindle a is securely mounted thereon,but so as to revolve freely. To it, by set-screws b', keys, or otherequivalent device, the cone of driving-pulleys bis secured.

The bearings of the spindle a are oiled through the cups a. Thei'orwardend of the spindle a terminates in a boxed head, in which is insertedthe chuck a', in which latter, by pins c', the die-holders c are hinged,with sufficient room for the latter to open and close therein. Thethreading-dies c are adjusted in the die-holders by set-screws or inother usual way.

In the hollovr spindle a is a rod, m, the forward end of which screwsinto a hub, u, which latter is arranged inside the heel ends ofthedie-holders c, and it is connected with each die-holder by a toggle,e, and these parts are so arranged that, with the forward thrust of therod m and hub n, the toggles e, acting on the die-holders c, will closethe dies c on the bolt, and the backward thrust oi' the rod m will, by areverse movement in the parts named, open the dies and release the bolt.

Extending along lengthwise of the frame A, and one on each side of thedevices described, is a pair of sliding rods, ff', supported by andmoving longitudinally in any suitable bearings j. These rods extendforward beyond the threading-dies, as shown, and carry at their outerends a cross-bar, g, which latter is moved toward and from the dies c bymeans of a lever, g', pivoted to the lugs g, and with its lower endengaging any suitable fulerum. That shown in the drawing consists of arod, h, which extends out from one of the legs of the frame A, and isslotted at or near its outer end to receive the lower end of the leverg.

Passing over the end of the rod h, and outside the lever g', is anadjustable collar, h', by which to change the point of leverage, so asto adapt the machine to the threading ot'bolts of different lengths ofshanks.

On the rear end of one of the sliding rods f orf', by a set-screw or itsequivalent, is adjustably attached one end ot' a knocking-arm orknocker, k, the other end of which slides on the rod m at any suitablepoint back of the toggle e, and for this purpose it has an eye, k', orother like device.

On the rod m, outside the knocker-eye 7s', is an adjustable collar, I,and inside the knockereye la is an abutment, d, the lateral faces of'which are inclined forward, as shown at s. It is held in place at anydesired point of adjustment by two adjustable collars, Z Z, one on eachside, each secured by a setscrew, in the usual way. I

In each lateral face 'of the abutment d, at the bases of the inclines s,'is a slight groove, s', and the opposite endof each incline sterminates in a shoulder, s, Fig. 4.

The arms p each carry a socketed head, p', and in each head is awedge-shaped catch, o, supported bya spiral spring, o. Fig. 5`shows theform of the catch-head. Figs. 1 and 2 show the adjustments of theseparts when the dies are closed ready to commence workthe edges ot' thewedge-shaped catch-heads o in the grooves s.

For the purpose of holding the bolt while it is being threaded, Iadjust-on the cross-bar g, by dovetail joints, as illustrated in Fig. 1,two die-blocks,zz ,Fi g.2. One of these die-blocks, z, works back andforth'on the cross-bar g by means of the shank of a screw, y, whichpasses through it, the threaded end of the screw y working in a tappedeye of the other die-block,

The screw is operated by a hand-wheel, y'. The die-block z is Xedlyattached to the cross-bar g, or adjustably attached by means of aset-screw.

The die-blocks z z carry griping-dies .fr Fig. 2, which gripe the boltand hold it while it is being threaded. Y Y

To adapt the machine for feedin gin bolts of different sizes, thedie-block z' may be set forward or backward, or the die w therein may beset in or out, and the die-block z carried forward or backward byturning the handwheel y; also, by this last-named motion, the dies w xare made to bite or release the bolts while the machine is in operation.

The bolt to be threaded being placed in the position described-that is,griped by the dies a: x', and with its point a little short of thethreading-dies c, the latter being closed-the vmachine is then in theposition shown in Figs.

l and 2. By the lever g the point of the bolt is then brought to theopening of the threading-dies c. These latter, being rotated, take abite on the bolt, draw itin, and thread it in the usual way. The bolt,while being thus drawn in, draws with it the die-heads z z', cross-barg, to which they are attached, and imparts a longitudinal motion to theparallel sliding rods j' f.

When the desired length of screw-thread has been cut, the eye 7c of theknocker-arm 7c strikes the collar l on the rea-r end of the rod m, andforces the rod backward. By this motion the abutment d is released fromthe hold ofthe catches o, and passes back between them.

As soon as the catches o leave the grooves s their inclined faces strikethe inclined faces s of the abutment d, and, under the pressure of thesprings o', force it back with a sudden instantaneous throw, and with itthe rod m. rIhis motion causes the toggle e to open the threading-diesc", as already explained, but with a quick motion. By this means I cutthe desired length of perfect thread, and no more, whereas in many, ifnot all, the machines heretofore in use the threading-dies have beenopened gradually or bya slow motion, in which case the thread of thebolt gradually tapers out into the shank. The operator then grasps thewheel y' and withdraws and loosens the finished bolt, both at the sametime. A new bolt is put in and the die-block a' turned up to gripe it.

The withdrawal' of the boltV has carried for- Y Ward the parallelsliding rods f and knocker 7c, so as to bring the knocker-eye 7c'against the collar l', whereby the abutment d' is driven forward betweenthe catches 0 till the edges of the latter rest again in the grooves s.The rod m is also thrust forward by the same action, and it, actingthrough the toggles e, closes the threading-dies, and the workcontinues. l

By the proper adjustments of knocker 7c, collars l l l, and abutment d,the machine can be readily adapted to 'cutting any desired length ofthread on bolt-Shanks of different lengths.

Underneath the threadin g-dies c" I arrange a drip-pan, t, sliding orremovable, for convenience in cleaning, and witha finely-perforatedbottom, as shown. Underneath this is a table, e, inclined so that theoil dripping down thereon through the perforationst' of the pan aboveshall run into a receptacle or vat, fw, whence it maybe drawn offthrough a cock, g. In this way I avoid wastage in either iron or oil,and keep the machinery and machine-room clean and in good condition.

What I claim as my invention, and desire to secure by Letters Patent, is

1. The abutment d, with its inclined lateral faces s, a groove, s', atthe base of each ineline, and a shoulder or stop, s, at the opposite endof each incline, and the combination of such abutment with the rod m andwedgeshaped catches o, reciprocating knocker 7c, an d collars Z l',substantially asand for t-he purposes set forth.

2. The subject-matter of the foregoing claim, in combination with atoggle, e, leading to each of the die-holders of a screw-cuttin gmachine, substantially as described.

3. The combination of the abutment d, constructed substantially asdescribed, catches o, knocker la, operated by any suitable means, androd m, having stops l l', in connection with any suitable mechanism foropening the dies.

4. The arrangement of drip-pan t with perforated bottom, inc-lined tablefu, and receptacle or vat w, for receiving and drawing off the oil,substantially as described.

In testimony whereof I, the said J AMES S. ATKINSON, have hereunto setmy hand.

JAMES S. ATKINSON.

Witnesses W. N. PAXToN, G. H. GHRIsrY.

